Method ofr controlling the displacement of a part, displaced by an electromotor, of a closure device in a motor vehicle

ABSTRACT

The invention relates to a method for controlling the displacement motion of a part, moved by an electromotor, of a closure device in a motor vehicle, for example, a window pane control, in the doors of the motor vehicle. A jamming incident is identified by a comparison of at least one status value of the electromotor or of the closure device which status value signifies a jamming incident, for example the motor current or the displacement speed, which a characteristic value that is significant for a jamming incident. In addition, the position of movable body parts, in particular the doors, is detected and the control of the displacement motion is adapted, in accordance with the identification of a jamming incident and the position of the body parts. If the result of the comparison indicates a jamming incident, the electromotor is Stopped for a predetermined short period of time that is preferably hardly perceptible, or the motor is reversed. A verification is made whether, based on a predetermined first position of the body part, the position has altered or is altering during a predetermined time range prior to and/or after the occurrence of the comparison result that indicates a jamming incident. If this is the case, the displacement motion is continued in the closure direction, if not, it is assumed that a jamming incident has occurred and the electromotor is reversed, or the reversing action is continued. The Stopping or reversing time period is preferably of such a short duration that the displacement motion of the moving part in the opposite direction is not perceptible, at least to the naked eye.

[0001] The invention relates to a method for controlling thedisplacement motion of a part of a closure device that is driven by anelectric motor in a motor vehicle in accordance with the preamble ofclaim 1.

[0002] Such methods are known from German Patent Publications DE 40 20351 C2 and DE 197 45 597 A1. For recognizing a jamming incident at leastone status value of the electric motor and/or of the closure device iscompared with a characteristic value that defines a jamming incident.Status values for this purpose are, for example, the displacement force,the motor current, the r.p.m. or the torque moment of the motor. Onecould also think of detecting the positional change of the closuredevice or the speed thereof. The jamming incident is then defined byrespective characteristic values, for example, a maximum displacementforce, a maximum motor current, a minimum r.p.m. and so forth.

[0003] In this context, due to external influences, particularly theclosing of vehicle doors and of other movable body parts, forces may beeffective on the closure device, which forces oppose the displacementmotion. Thus, the status values reach the characteristic values, if theforces have a corresponding strength, for a jamming incident therebycausing an emergency shut-off. The shut-off is characterized by areversing, that is, an instantaneous opposite power supply to the motorwhich leads to an unmistakable backward motion of the moving part,frequently even into the completely open position thereof. While thiscannot be avoided in an actual jamming incident for the protection ofpossibly pinched-in persons or body parts, a consumer could interpretthis usually complete reversal as a failure function in the case thatexternal influences caused the reaching of the comparing results whichindicate a jamming incident.

[0004] Thus, German Patent Publication DE 40 20 351 C2 suggests sensingthe acceleration forces acting on the vehicle body by a sensor and totake these forces into account as a base level. However, a detailedembodiment is not disclosed. If one takes into account the strength anddynamic of the acceleration forces acting on a vehicle body, it remainsquestionable whether and how such taking into account is technicallyrealizable in a suitable manner.

[0005] On the other hand, German Patent Publication 197 45 597 A1suggests controlling the displacement force of the motor as a sum of aforce necessary for the displacement of the part and an adjustableexcess force, whereby the displacement force and/or the excess force arecontrolled in closed loop fashion in response to the forces acting onthe vehicle body. Even if one disregards the unclear determination ofthe force necessary for the displacement of the part and the effort andexpense for an exact closed loop control of the displacement forces ofthe motor, the effort and expense for taking the external forces intoaccount has proven itself to be substantial.

[0006] Alternatively, a variation of the displacement and/or excessforce is controlled in closed loop fashion in response to opening andclosing procedures of movable body parts in that the position of themovable body parts is ascertained by sensors and a variation.Particularly opening and closing procedures are recognized. In such acase an increase of the excess force or even discontinuing thepinching-in protection is suggested. Thus, however the pinching-indanger is put-up with. Additionally, this requires that the controldevice receives a signal from the sensors regarding the position changeeven prior to the occurrence of a pinching-in recognition.

[0007] Thus, it is an object of the invention to provide an alternativemethod for controlling the displacement motion of closure device, whichmethod makes possible, on the one hand, a reliable and early recognitionof a jamming incident and which, on the other hand, takes into accountin a simple manner external influences by movable vehicle body parts.

[0008] This object is achieved by the characterizing features ofclaim 1. Advantageous further developments are to be taken from thedependent claims.

[0009] Thus, when a comparing result indicates that a jamming incidentexists, the electric motor is stopped for a predetermined, short timeduration, or alternatively, it is reversed. Thereby it is examinedwhether, within a given time range prior to and/or after the occurrenceof a comparing result indicating a jamming incident and starting from apredetermined first position of the vehicle body part, a change of theposition occurred and/or is occurring.

[0010] If within this time range the position signal indicates a changerelative to the first position of a vehicle body part, the displacementmotion in the closing direction is continued, otherwise a jammingincident is assumed to exist and the electric motor is reversed and/orthe reversing is continued.

[0011] Thereby, the time duration may be determined corresponding to thereaction time of the sensor and the traveling time of the positionsignal up to the control to be so short that the customer does notnotice this pause or the short time reversing during this time durationor at least it is not noticed as a disturbance. Particularly, timedurations of about 150 to 100 msec or even shorter have been found to besufficient to distinguish, by monitoring the sensors, between an actualjamming incident and an occurrence of comparable force caused by theclosing of a vehicle body part, particularly the door. If one takes intoaccount that the moved part including the mechanical components firsthave a substantial inertia and thus hardly come to an actual stop withina time duration of about 100 msec even if a reversing current is appliedand additionally the time duration is too short with regard to thereceptivity of the human eye, it becomes clear, that the customer willnot notice even a reversing introduced for a short duration. On theother hand, the short duration stopping or the reversing have acritically higher safety in case of an actual jamming incident comparedto the known alternatives of the prior art of a threshold increase oreven a deactivation of the jamming protection.

[0012] A first further embodiment of the method is provided when acomparing result indicating a jamming incident and the first position ofthe vehicle body part are present simultaneously wherein first theelectric motor is stopped or reversed again for the predetermined timeduration and wherein the displacement motion is continued provided thatwithin this time duration the position signal indicates a change of avehicle body part relative to the first position. Thus, the case iscovered in which the position signal arrives with such a delay, forexample due to a slow data transmission, that the recognition hasalready responded in the case of respectively strong shock vibrations.

[0013] A second further development of the method is results, ifstarting from the given first position, a change of the position of thevehicle body part is recognized and if within a predetermined time rangestarting with this change, a comparing result occurs indicating ajamming incident. In this case the electric motor is also stopped forthe predetermined time duration and the displacement motion is thencontinued, whereby the time duration of this stop does not need to beidentical to that of the first further development, preferably it isclearly shorter. This further development thus covers the case whereinan already recognized door closing operation is immediately followed bya jamming incident.

[0014] The characteristic values for comparing with the status valueswhich are significant for a jamming of a part, are adapted at a firstposition, particularly at an open position of a vehicle body part in adirection of a timewise later jamming recognition. An adaptation in thedirection of a timewise later jamming recognition means for example anincrease of the jamming characteristic value of the motor current or areduction of the characteristic value of the r.p.m. and/or thedisplacement speed. Besides that, the characteristic values can beadapted for the comparing with the status values that are significantfor the jamming of a part in response to the position and the motiondirection of the movable part.

[0015] In a preferred manner the jamming recognition thus remainsbasically in an active state even after the end of the time duration ofthe stopping or of the reversing, if indicated, with relatively highcharacteristic values, so that a jamming incident occurring actuallysimultaneously with the closing of a door, is recognized even if thedisplacement is continued and a respective emergency shut-off isinitiated.

[0016] The invention shall be explained in more detail in the followingwith reference to an example embodiment and the Figures.

BRIEF DESCRIPTION OF THE FIGURES

[0017]FIG. 1 shows the sequence of the method and the curve of the motorcurrent and of the jamming current characteristic value when theposition of the door is changed;

[0018]FIG. 2 shows the door position sensor signal;

[0019]FIG. 3 shows the sequence of the method with a short durationreversing; and

[0020]FIG. 4 shows the motion change of the moved part per time unitduring the method.

[0021]FIG. 1 shows the curve of the motor current I(t) of the electricmotor as a status value that is significant for a jamming. In an analogmanner other status values can also be used, as explained above, forexample the displacement speed of the closure device. The motor currentI(t) is compared with the jamming current characteristic value, which,in the especially preferred embodiment of FIG. 1, assumes the values 10,11, 12 or 13, whereby the selection of the value takes place in responseto certain occurrences and will be explained in more detail below.

[0022]FIG. 2 shows the position signal of a sensor which senses theposition of a movable vehicle body part, in this case a door. The sensorin this example is a door switch with the signal states door open ordoor closed. For faults in the jamming recognition the vibration shockwhen closing the door is thereby especially of interest.

[0023] When a comparing result in t_(x) indicating a jamming incident ispresent, the electric motor is stopped for a predetermined time durationT_(Stop) and the motor current I(t) drops. It is checked whether withina predetermined time range t_(x)±ΔT prior to and/or after the occurrenceof the comparing result that indicates the jamming incident, andstarting from a given first position, in this case “door open”, of thevehicle body part, a change in the position (door=>closed) has occurredor is occurring. In this case the displacement motion is continued as isshown at t₄ in FIG. 1. Otherwise, a jamming incident is assumed and theelectric motor is reversed.

[0024] The observation of the time range t_(x)±ΔT prior to and/or afterthe occurrence of the jamming incident at t_(x), takes into account theconnection of the position sensor to the control system which connectionmay quite differ in the different systems. Thus, when a directconnection, for example of the door switch to the door control devicewhich is responsive for the displacement control of the window panes,the signal, the position change can be actually evaluated even prior tothe recognition of the jamming incident which was caused by vibrationshock and thus is not real. However, if the door switch is interrogatedthrough a central CAN-bus, it is possible, until the arrival of theinformation regarding the position change, that the jamming incidentcaused by vibration shock has already been recognized. Also in this casean erroneous reversing can be avoided by the stop for the predeterminedtime duration T_(Stop) when an immediately preceding closing of the dooris recognized without the need for cancelling the jamming protection.

[0025] The length and orientation of the time range (t_(x)±ΔT may, butdoes not need to, lie prior to or after the occurrence of the jammingincident at t_(x). Particularly, this time range does not need to besymmetrical relative to the jamming point of time t_(x). By way of thistime interval the following are taken into account: the delayedpropagation of a vibration shock in response to a position change of avehicle body part, which propagation must be individually adapted foreach vehicle type, the delay in the response of the jamming recognition,and the travel time of the position signal.

[0026] If one can start with the assumption that the position changealways takes place afer the response of the jamming recognition, a firstfurther development of the method results. Thereby, the electric motoris Stopped again for the predetermined time duration T_(Stop) if thecomparing result (i(t)=11), that indicates the presence of a jammingincident, and the first position of the vehicle body part (door open) att_(x) are present simultaneously, and the displacement motion iscontinued if within this time duration the position signal indicates achange relative to the first position of a vehicle body part. The timerange to be considered and shown in FIG. 1 as (t_(x)±ΔT) thencorresponds to T_(Stop). In that case a position change is expected onlystarting at t_(x). In a simple example embodiment this means that theposition of the doors of the vehicle is monitored and that the electricmotor is first Stopped for a predetermined time duration if thecomparing result, which indicates a jamming incident, and the positionsignal, which indicates an open door, are present simultaneously. Thenthe displacement motion is continued if within this time duration a doorclosing is indicated.

[0027] A second further development of the method is obtained in thereverse case when the position change can always be recognized prior tothe response of the jamming recognition. If, starting from thepredetermined first position (door open) a change in the position of thevehicle body part is recognized and if a comparing result indicating ajamming incident occurs within a predetermined time range, starting withthis change, the electric motor is also Stopped in this case for thepredetermined time duration and the displacement motion is thencontinued. Thereby, the time duration of this Stop does not need to beidentical to that of the first further embodiment, preferably it isclearly shorter.

[0028] The length of the time duration T_(Stop) is thereby selected tobe relatively short and takes into account, above all, the signal traveltime and the decay of the vibration shock. Experiments have shown thatthe time duration for T_(Stop) of about 100 msec and below aresufficient for this purpose. In the most advantageous case the part tobe moved thereby does not at all come to a full Stop. This shortinterruption, in any case, is not noted by the customer or at least itis not noted as being disturbing.

[0029] A multitude of possibilities are available for the renewedstartup required for continuing the displacement motion, in order toavoid or limit the danger of jamming also in this instance. The renewedstart-up causes a higher start-up current, however, this higher start-upcurrent exceeds, between t₄ and t₅, the low thresholds 10 or 11 that arecustomary for the jamming recognition, only for such a short time thatthe pane has not moved at all in this time range or it has made onlysuch insignificant advance that a jamming cannot occur.

[0030] Further, the characteristic values for comparing with the statusvalues that are significant for a jamming of the part, can be adapted bytaking into account the position and motion direction of the movablepart. This takes place, for example, in this example embodiment, in thatfirst between t₀ and t₁ the start-up of the pane in the inner area ofthe door, where there is no danger of jamming, is compared with a highthreshold 13. Starting with t₁ a switch to a clearly lower threshold 11is performed, whereby threshold 11 is somewhat higher than threshold 10.Namely, an open position of a vehicle body part is present, in this caseof the door, so that in this especially preferred embodiment thecharacteristic values for comparing with the status values, that aresignificant for a jamming of the part, are adapted in the directiontoward a timewise later jamming recognition, that is: they are increasedfrom 10 to 11, in order to neutralize smaller vibration shocks alreadyin this manner.

[0031] For the renewed start-up at t₄ the characteristic value istemporarily increased to the threshold 12, which however can be selectedto be smaller than 13. Starting with t₅, preferably even before theactual beginning of the continuation of the displacement motion of thepane, the characteristic value is also switched to the lowest threshold10, because the door is now closed.

[0032] Especially preferred is the use of the method known from GermanPatent Publication DE 197 10 388 A1 of the applicant, wherein in eachphase including the start-up phase, a jamming can be recognized at anytime, so that especially also during a renewed start-up a jamming iscertainly recognized.

[0033]FIG. 3 still illustrates the alternative embodiment wherein, whena comparing result is present indicating a jamming incident, theelectric motor is even reversed for a time duration T_(rev), that is,the motor is energized in the opposite direction. Thus, the motorcurrent in FIG. 3 becomes substantially negative. Thereby it is againtested, in an analog manner, at the door sensor, whether in thepredetermined time range t_(x)±ΔT prior to and/or after the occurrenceof the comparing result indicating the jamming incident and startingfrom a predetermined first position, in this case “door open”, of thevehicle body part, a position change has taken place (door=>closed) oris taking place. In this case the displacement motion is again continuedin the closing direction as also seen at t₄ in FIG. 3. Otherwise ajamming incident is assumed and reversing of the electric motor iscontinued.

[0034]FIG. 4 thereby additionally sketches the actual motion change ofthe part being moved per unit of time during this method, particularlyduring the reversing according to FIG. 3, and it makes clear that theactual reverse motion of the part being moved also during reversing isso small and of such short duration due to the inertia of the mechanicalsystem that the customer will not be able to notice this with the nakedeye. This is a fact for time durations of 100 msec solely due to thelimits of perception. If one additionally takes into account the ratioof the time duration T_(rev) of the reverse energizing to the timeduration T_(ruc) of the actually backwards directed motion of the movedpart, it becomes clear, that time durations clearly above 100 msec wouldstill be sufficient to assure that the reverse motion is not perceptiblefor the customer's naked eye. The limits will differ from one system tothe other. One can start from the assumption that even a reverseenergizing or a Stopping in the range of one second is hardly noticeableon the actual motion change of the pane.

[0035] A further alternative not shown in the Figures results form thecombination of the two alternatives of reversing and Stopping in atimely sequence, that is, one first energizes reversed for a shortduration, for example in order to actually and quickly bring the movedpart to a Stop, to which subsequently is added a Stop phase, that is aphase without an energizing current, provided a position change of thevehicle body part has not yet been recognized at that time. An actuallyopposite sequence is also possible.

1. Method for controlling the displacement motion of a part of a closuredevice driven by an electric motor in a vehicle, (a) whereby a jammingrecognition takes place by a comparing of at least one jammingsignificant status value (I(t)) of the electric motor or of the closuredevice with a characteristic value (10, 11, 12, 13) that is significantfor a jamming incident, (b) additionally the position (open, closed) ofmovable vehicle body parts (door), particularly of the doors, is sensed,and (c) the control of the displacement motion is adapted in response tothe jamming recognition and the position of the vehicle body parts,characterized in that (d) when a comparing result is present at (t_(x))indicating a jamming incident, the electric motor is (d1) Stopped for apredetermined time duration (T_(Stop)) or (d2) reversed, (e) and a testis made whether in a predetermined time range (t_(x)±ΔT) prior to and/orafter the occurrence of the comparing result indicating a jammingincident, (f) starting from a first predetermined position (door open)of the vehicle body part, a change in the position (door=>closed) hastaken place or is taking place, (g) in which case the displacementmotion in the closing direction is continued, and (h) otherwise ajamming incident is assumed and the electric motor is reversed or thestarted reversing is continued.
 2. Method according to method of claim1, characterized in that (a) if the comparing result indicating ajamming incident and the first position of the vehicle body part (dooropen at t_(x)) are present simultaneously (b) the electric motor isfirst (b1) Stopped for the predetermined time duration (T_(Stop)), or(b2) it is reversed, and (c) in case the position signal indicateswithin this time duration (T_(Stop)) a change relative to the firstposition of a vehicle body part (door=>closed), the displacement motionis continued, (d) otherwise a jamming incident is assumed and theelectric motor is reversed.
 3. Method according to method of claim 1,characterized in that (a) in case, starting from the predeterminedposition, a change in the position of the vehicle body part (dooropen=>door closed) is recognized, and (b) within a predetermined timerange starting with this change, a comparing result occurs indicating ajamming incident, (c) the electric motor is Stopped for thepredetermined time duration (T_(Stop)) and thereafter the displacementmotion is resumed.
 4. Method of claim 2, characterized in that theposition (open, closed) of the vehicle doors is monitored and that, ifthe comparing result indicating a jamming incident and a position signalindicating an open door are present simultaneously, the electric motoris first Stopped for a predetermined time duration (T_(Stop)) and thenthe displacement motion is continued if within this time duration aclosing of the door is indicated.
 5. Method of one of the precedingclaims, characterized in that the characteristic values for comparingwith the status values which are significant for a jamming of the part,are adapted, when a vehicle body part is in an open position, in adirection toward a timewise later jamming recognition (11>10).
 6. Methodof one of the preceding claims, characterized in that the characteristicvalues for comparing with the status values, which are significant forthe jamming of the part, are adapted in response to the position and themotion direction of the movable part.
 7. Method of one of the precedingclaims, characterized in that the time duration (T_(Stop)) for theStopping or reversing is determined to be so short that the moved partcannot be perceived, at least not with the naked eye, as being moved inthe opposite motion direction.
 8. Method of claim 7, characterized inthat the time duration (T_(Stop)) for Stopping or reversing isdetermined to be less than 150 msec.
 9. Method of claim 8, characterizedin that the time duration (stop) for Stopping or reversing is determinedto be less than 100 msec.
 10. Method of one of the preceding claims,characterized in that (a) when a comparing result is present (at t_(x))indicating a jamming incident the electric motor is (b) reversed for afirst predetermined time duration (T_(rev)) and (c) is Stopped for afollowing predetermined time duration (T_(Stop)).
 11. Method of one ofthe claims 1 to 9, characterized in that (a) when a comparing result ispresent (at t_(x)) indicating a jamming incident the electric motor is(b) Stopped for a first predetermined time duration (T_(Stop)), and (c)is reversed for a following predetermined time duration (T_(rev)).